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How to create a unique index on a NULL column?
...f uniques" -- NULL is a special value in SQL (similar in many ways to NaN) and needs to be treated accordingly. It's actually a failure in in SQL Server to honor various SQL specifications: here is a link for a request for the "correct implementation" for what it is worth: connect.microsoft.com/SQLS...
How to replace an entire line in a text file by line number
... For me it says: sed: -e expression #1, char 26: unknown option to ``s' and my line is: sed -i '7s/.*/<param-value>http://localhost:8080/ASDF/services/REWS.REWSHttpSoap12Endpoint/</param-value>/' $TCE_SVN_HOME\trunk\tce\EWC\WebContent\WEB-INF\web.xml. Any idea?
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HTTP GET with request body
...ther words, any HTTP request message is allowed to contain a message body, and thus must parse messages with that in mind. Server semantics for GET, however, are restricted such that a body, if any, has no semantic meaning to the request. The requirements on parsing are separate from the requirement...
html5 - canvas element - Multiple layers
...ver, you could layer multiple <canvas> elements on top of each other and accomplish something similar.
<div style="position: relative;">
<canvas id="layer1" width="100" height="100"
style="position: absolute; left: 0; top: 0; z-index: 0;"></canvas>
<canvas id="layer...
Pandoc markdown page break
Recently I started using Pandoc markdown which seems a good alternative to LaTeX, as my document does not have many mathematical formulas, and I do not have ANY experience with LaTeX, which combined with less than 2 week submission deadline makes it a good solution.
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Is “else if” a single keyword?
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They are not a single keyword if we go to the draft C++ standard section 2.12 Keywords table 4 lists both if and else separately and there is no else if keyword. We can find a more accessible list of C++ keywords by going to cppreferences section on keywords.
The grammar in sectio...
Select last row in MySQL
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I just ran this over 20m rows and it was very fast. I assume there's some kind of special case for handling this query. (EDIT: MySQL 5.7, InnoDB engine)
– Daniel Buckmaster
Oct 29 '18 at 2:20
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What is the difference between ndarray and array in numpy?
What is the difference between ndarray and array in Numpy? And where can I find the implementations in the numpy source code?
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What's the difference between ES6 Map and WeakMap?
Looking this and this MDN pages it seems like the only difference between Maps and WeakMaps is a missing "size" property for WeakMaps. But is this true? What's the difference between them?
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Easiest way to check for an index or a key in an array?
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To check if the element is set (applies to both indexed and associative array)
[ ${array[key]+abc} ] && echo "exists"
Basically what ${array[key]+abc} does is
if array[key] is set, return abc
if array[key] is not set, return nothing
References:
See Parameter Expa...